EFFECTS OF TREATMENT ON AIRWAY DYNAMICS AND RESPIRATORY MUSCLE STRENGTH IN PARKINSONS-DISEASE

To investigate how treatment can affect airway dynamics and respirator y muscle strength in Parkinson's disease (PD), we assessed maximum eff ort inspiratory and expiratory mouth pressures (MIP and MEP), oscillat ory impedance, and maximum expiratory and inspiratory flow-volume curv es (MEFV and MIFV) in 10 patients (8 male and 2 female; mean age 51 +/ - 5.3 yr, SD) after temporary interruption of antiparkinsonian therapy (off) and during continuous subcutaneous infusion of a direct stimula nt of dopamine receptors, apomorphine (on). Treatment improved neurolo gic scores (off 25 +/- 5, on 9 +/- 5, modified Webster scale, p < 0.00 1), MEP (off 45 +/- 25, on 63 +/- 29 cm H2O, p = 0.003), and peak insp iratory flow (PIF; off 3.83 +/- 1.6, on 4.37 +/- 1.7 L/s, p = 0.028). Maximum inspiratory pressure was very low off treatment(-25 +/- 16 cm H2O) and improved moderately with apomorphine (-33 +/- 17 cm H2O) (p = 0.064). Total respiratory resistance during tidal breathing was norma l in 9 patients both off and on treatment despite, in some cases, dram atic changes in MEFV and MIFV curves. These results suggest that abnor malities of the flow-volume curves may be due to problems in the rapid activation and coordination of contraction of upper airways and chest wall muscles during forced maneuvers, which is improved by apomorphin e treatment.